This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2001-135752, filed May 7, 2001, the entire contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a laser light source apparatus using a semiconductor laser array.
2. Description of the Related Art
A semiconductor laser has a high electro-optic conversion efficiency and luminance equal to that of a YAG laser. The semiconductor laser has ideal characteristics as a solid laser.
A direction parallel to the active layer of a semiconductor laser is defined as an x direction, and a direction perpendicular to the active layer is defined as a y direction. The beam divergence angle of a semiconductor laser beam emitted from a semiconductor laser differs between the x direction and the y direction because the light-emitting portion serves as, e.g., a 1-xcexcmxc3x97100-xcexcm surface illuminant. Hence, when the semiconductor laser is applied to a normal optical system that is designed to be symmetrical with respect to the laser optical axis, it is difficult to focus the semiconductor laser beam to a small region.
Especially, a semiconductor laser array has a plurality of light-emitting portions that emit a semiconductor laser beam. In the semiconductor laser array, each light-emitting portion has a size of 1 xcexcmxc3x97100 xcexcm. A number of emitters are arrayed in the x direction at pitches as small as 0.2 to 0.5 mm. For this reason, it is more difficult to focus the semiconductor laser beam emitted from the semiconductor laser array to a small region.
An optical system that focuses a semiconductor laser beam emitted from a semiconductor laser array is described in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 8-307017. According to the description in this prior art, a micro-collimator lens array is arranged in correspondence with each light-emitting portion of a semiconductor laser array. The micro-collimator lens array is formed to have a periodical structure.
Another optical system which focuses a semiconductor laser beam is described in, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2000-98191. This prior art describes an optical system which efficiently makes a semiconductor laser beam emitted from a two-dimensional semiconductor laser array incident on an optical fiber and outputs the laser beam. That is, the optical system comprises a collimator lens array and a condenser lens array. The collimator lens array collimates the semiconductor laser beam in at least one of the vertical and horizontal directions of a plurality of light-emitting portions that are two-dimensionally arrayed. The condenser lens array focuses the semiconductor laser beam in both of the vertical and horizontal directions of the plurality of light-emitting portions that are two-dimensionally arrayed.
To obtain a large output, a plurality of semiconductor laser arrays are stacked in the y direction. However, the above prior arts disclose no optical system which efficiently focuses a semiconductor laser beam emitted from each of the plurality of stacked semiconductor laser arrays at all.
It is an object of the present invention to provide a laser light source apparatus capable of efficiently focusing each semiconductor laser beam emitted from a semiconductor laser array.
A laser light source apparatus according to a main aspect of the present invention comprises a semiconductor laser light source having a plurality of light-emitting portions which emit semiconductor laser beams, a collimator section which collimates the semiconductor laser beams emitted from the light-emitting portions in the semiconductor laser light source, and a laser beam deflecting section which deflects optical axes of the semiconductor laser beams, which are collimated by the collimator section, to be parallel to each other.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.